Initial import

1 files changed, 1305 insertions, 0 deletions

diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
new file mode 100644
index 000000000..af3be1914
--- /dev/null
+++ b/drivers/edac/edac_mc.c
@@ -0,0 +1,1305 @@
+/*
+ * edac_mc kernel module
+ * (C) 2005, 2006 Linux Networx (http://lnxi.com)
+ * This file may be distributed under the terms of the
+ * GNU General Public License.
+ *
+ * Written by Thayne Harbaugh
+ * Based on work by Dan Hollis <goemon at anime dot net> and others.
+ *	http://www.anime.net/~goemon/linux-ecc/
+ *
+ * Modified by Dave Peterson and Doug Thompson
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/smp.h>
+#include <linux/init.h>
+#include <linux/sysctl.h>
+#include <linux/highmem.h>
+#include <linux/timer.h>
+#include <linux/slab.h>
+#include <linux/jiffies.h>
+#include <linux/spinlock.h>
+#include <linux/list.h>
+#include <linux/ctype.h>
+#include <linux/edac.h>
+#include <linux/bitops.h>
+#include <asm/uaccess.h>
+#include <asm/page.h>
+#include <asm/edac.h>
+#include "edac_core.h"
+#include "edac_module.h"
+#include <ras/ras_event.h>
+
+/* lock to memory controller's control array */
+static DEFINE_MUTEX(mem_ctls_mutex);
+static LIST_HEAD(mc_devices);
+
+/*
+ * Used to lock EDAC MC to just one module, avoiding two drivers e. g.
+ *	apei/ghes and i7core_edac to be used at the same time.
+ */
+static void const *edac_mc_owner;
+
+static struct bus_type mc_bus[EDAC_MAX_MCS];
+
+unsigned edac_dimm_info_location(struct dimm_info *dimm, char *buf,
+			         unsigned len)
+{
+	struct mem_ctl_info *mci = dimm->mci;
+	int i, n, count = 0;
+	char *p = buf;
+
+	for (i = 0; i < mci->n_layers; i++) {
+		n = snprintf(p, len, "%s %d ",
+			      edac_layer_name[mci->layers[i].type],
+			      dimm->location[i]);
+		p += n;
+		len -= n;
+		count += n;
+		if (!len)
+			break;
+	}
+
+	return count;
+}
+
+#ifdef CONFIG_EDAC_DEBUG
+
+static void edac_mc_dump_channel(struct rank_info *chan)
+{
+	edac_dbg(4, "  channel->chan_idx = %d\n", chan->chan_idx);
+	edac_dbg(4, "    channel = %p\n", chan);
+	edac_dbg(4, "    channel->csrow = %p\n", chan->csrow);
+	edac_dbg(4, "    channel->dimm = %p\n", chan->dimm);
+}
+
+static void edac_mc_dump_dimm(struct dimm_info *dimm, int number)
+{
+	char location[80];
+
+	edac_dimm_info_location(dimm, location, sizeof(location));
+
+	edac_dbg(4, "%s%i: %smapped as virtual row %d, chan %d\n",
+		 dimm->mci->csbased ? "rank" : "dimm",
+		 number, location, dimm->csrow, dimm->cschannel);
+	edac_dbg(4, "  dimm = %p\n", dimm);
+	edac_dbg(4, "  dimm->label = '%s'\n", dimm->label);
+	edac_dbg(4, "  dimm->nr_pages = 0x%x\n", dimm->nr_pages);
+	edac_dbg(4, "  dimm->grain = %d\n", dimm->grain);
+	edac_dbg(4, "  dimm->nr_pages = 0x%x\n", dimm->nr_pages);
+}
+
+static void edac_mc_dump_csrow(struct csrow_info *csrow)
+{
+	edac_dbg(4, "csrow->csrow_idx = %d\n", csrow->csrow_idx);
+	edac_dbg(4, "  csrow = %p\n", csrow);
+	edac_dbg(4, "  csrow->first_page = 0x%lx\n", csrow->first_page);
+	edac_dbg(4, "  csrow->last_page = 0x%lx\n", csrow->last_page);
+	edac_dbg(4, "  csrow->page_mask = 0x%lx\n", csrow->page_mask);
+	edac_dbg(4, "  csrow->nr_channels = %d\n", csrow->nr_channels);
+	edac_dbg(4, "  csrow->channels = %p\n", csrow->channels);
+	edac_dbg(4, "  csrow->mci = %p\n", csrow->mci);
+}
+
+static void edac_mc_dump_mci(struct mem_ctl_info *mci)
+{
+	edac_dbg(3, "\tmci = %p\n", mci);
+	edac_dbg(3, "\tmci->mtype_cap = %lx\n", mci->mtype_cap);
+	edac_dbg(3, "\tmci->edac_ctl_cap = %lx\n", mci->edac_ctl_cap);
+	edac_dbg(3, "\tmci->edac_cap = %lx\n", mci->edac_cap);
+	edac_dbg(4, "\tmci->edac_check = %p\n", mci->edac_check);
+	edac_dbg(3, "\tmci->nr_csrows = %d, csrows = %p\n",
+		 mci->nr_csrows, mci->csrows);
+	edac_dbg(3, "\tmci->nr_dimms = %d, dimms = %p\n",
+		 mci->tot_dimms, mci->dimms);
+	edac_dbg(3, "\tdev = %p\n", mci->pdev);
+	edac_dbg(3, "\tmod_name:ctl_name = %s:%s\n",
+		 mci->mod_name, mci->ctl_name);
+	edac_dbg(3, "\tpvt_info = %p\n\n", mci->pvt_info);
+}
+
+#endif				/* CONFIG_EDAC_DEBUG */
+
+const char * const edac_mem_types[] = {
+	[MEM_EMPTY]	= "Empty csrow",
+	[MEM_RESERVED]	= "Reserved csrow type",
+	[MEM_UNKNOWN]	= "Unknown csrow type",
+	[MEM_FPM]	= "Fast page mode RAM",
+	[MEM_EDO]	= "Extended data out RAM",
+	[MEM_BEDO]	= "Burst Extended data out RAM",
+	[MEM_SDR]	= "Single data rate SDRAM",
+	[MEM_RDR]	= "Registered single data rate SDRAM",
+	[MEM_DDR]	= "Double data rate SDRAM",
+	[MEM_RDDR]	= "Registered Double data rate SDRAM",
+	[MEM_RMBS]	= "Rambus DRAM",
+	[MEM_DDR2]	= "Unbuffered DDR2 RAM",
+	[MEM_FB_DDR2]	= "Fully buffered DDR2",
+	[MEM_RDDR2]	= "Registered DDR2 RAM",
+	[MEM_XDR]	= "Rambus XDR",
+	[MEM_DDR3]	= "Unbuffered DDR3 RAM",
+	[MEM_RDDR3]	= "Registered DDR3 RAM",
+	[MEM_LRDDR3]	= "Load-Reduced DDR3 RAM",
+	[MEM_DDR4]	= "Unbuffered DDR4 RAM",
+	[MEM_RDDR4]	= "Registered DDR4 RAM",
+};
+EXPORT_SYMBOL_GPL(edac_mem_types);
+
+/**
+ * edac_align_ptr - Prepares the pointer offsets for a single-shot allocation
+ * @p:		pointer to a pointer with the memory offset to be used. At
+ *		return, this will be incremented to point to the next offset
+ * @size:	Size of the data structure to be reserved
+ * @n_elems:	Number of elements that should be reserved
+ *
+ * If 'size' is a constant, the compiler will optimize this whole function
+ * down to either a no-op or the addition of a constant to the value of '*p'.
+ *
+ * The 'p' pointer is absolutely needed to keep the proper advancing
+ * further in memory to the proper offsets when allocating the struct along
+ * with its embedded structs, as edac_device_alloc_ctl_info() does it
+ * above, for example.
+ *
+ * At return, the pointer 'p' will be incremented to be used on a next call
+ * to this function.
+ */
+void *edac_align_ptr(void **p, unsigned size, int n_elems)
+{
+	unsigned align, r;
+	void *ptr = *p;
+
+	*p += size * n_elems;
+
+	/*
+	 * 'p' can possibly be an unaligned item X such that sizeof(X) is
+	 * 'size'.  Adjust 'p' so that its alignment is at least as
+	 * stringent as what the compiler would provide for X and return
+	 * the aligned result.
+	 * Here we assume that the alignment of a "long long" is the most
+	 * stringent alignment that the compiler will ever provide by default.
+	 * As far as I know, this is a reasonable assumption.
+	 */
+	if (size > sizeof(long))
+		align = sizeof(long long);
+	else if (size > sizeof(int))
+		align = sizeof(long);
+	else if (size > sizeof(short))
+		align = sizeof(int);
+	else if (size > sizeof(char))
+		align = sizeof(short);
+	else
+		return (char *)ptr;
+
+	r = (unsigned long)p % align;
+
+	if (r == 0)
+		return (char *)ptr;
+
+	*p += align - r;
+
+	return (void *)(((unsigned long)ptr) + align - r);
+}
+
+static void _edac_mc_free(struct mem_ctl_info *mci)
+{
+	int i, chn, row;
+	struct csrow_info *csr;
+	const unsigned int tot_dimms = mci->tot_dimms;
+	const unsigned int tot_channels = mci->num_cschannel;
+	const unsigned int tot_csrows = mci->nr_csrows;
+
+	if (mci->dimms) {
+		for (i = 0; i < tot_dimms; i++)
+			kfree(mci->dimms[i]);
+		kfree(mci->dimms);
+	}
+	if (mci->csrows) {
+		for (row = 0; row < tot_csrows; row++) {
+			csr = mci->csrows[row];
+			if (csr) {
+				if (csr->channels) {
+					for (chn = 0; chn < tot_channels; chn++)
+						kfree(csr->channels[chn]);
+					kfree(csr->channels);
+				}
+				kfree(csr);
+			}
+		}
+		kfree(mci->csrows);
+	}
+	kfree(mci);
+}
+
+/**
+ * edac_mc_alloc: Allocate and partially fill a struct mem_ctl_info structure
+ * @mc_num:		Memory controller number
+ * @n_layers:		Number of MC hierarchy layers
+ * layers:		Describes each layer as seen by the Memory Controller
+ * @size_pvt:		size of private storage needed
+ *
+ *
+ * Everything is kmalloc'ed as one big chunk - more efficient.
+ * Only can be used if all structures have the same lifetime - otherwise
+ * you have to allocate and initialize your own structures.
+ *
+ * Use edac_mc_free() to free mc structures allocated by this function.
+ *
+ * NOTE: drivers handle multi-rank memories in different ways: in some
+ * drivers, one multi-rank memory stick is mapped as one entry, while, in
+ * others, a single multi-rank memory stick would be mapped into several
+ * entries. Currently, this function will allocate multiple struct dimm_info
+ * on such scenarios, as grouping the multiple ranks require drivers change.
+ *
+ * Returns:
+ *	On failure: NULL
+ *	On success: struct mem_ctl_info pointer
+ */
+struct mem_ctl_info *edac_mc_alloc(unsigned mc_num,
+				   unsigned n_layers,
+				   struct edac_mc_layer *layers,
+				   unsigned sz_pvt)
+{
+	struct mem_ctl_info *mci;
+	struct edac_mc_layer *layer;
+	struct csrow_info *csr;
+	struct rank_info *chan;
+	struct dimm_info *dimm;
+	u32 *ce_per_layer[EDAC_MAX_LAYERS], *ue_per_layer[EDAC_MAX_LAYERS];
+	unsigned pos[EDAC_MAX_LAYERS];
+	unsigned size, tot_dimms = 1, count = 1;
+	unsigned tot_csrows = 1, tot_channels = 1, tot_errcount = 0;
+	void *pvt, *p, *ptr = NULL;
+	int i, j, row, chn, n, len, off;
+	bool per_rank = false;
+
+	BUG_ON(n_layers > EDAC_MAX_LAYERS || n_layers == 0);
+	/*
+	 * Calculate the total amount of dimms and csrows/cschannels while
+	 * in the old API emulation mode
+	 */
+	for (i = 0; i < n_layers; i++) {
+		tot_dimms *= layers[i].size;
+		if (layers[i].is_virt_csrow)
+			tot_csrows *= layers[i].size;
+		else
+			tot_channels *= layers[i].size;
+
+		if (layers[i].type == EDAC_MC_LAYER_CHIP_SELECT)
+			per_rank = true;
+	}
+
+	/* Figure out the offsets of the various items from the start of an mc
+	 * structure.  We want the alignment of each item to be at least as
+	 * stringent as what the compiler would provide if we could simply
+	 * hardcode everything into a single struct.
+	 */
+	mci = edac_align_ptr(&ptr, sizeof(*mci), 1);
+	layer = edac_align_ptr(&ptr, sizeof(*layer), n_layers);
+	for (i = 0; i < n_layers; i++) {
+		count *= layers[i].size;
+		edac_dbg(4, "errcount layer %d size %d\n", i, count);
+		ce_per_layer[i] = edac_align_ptr(&ptr, sizeof(u32), count);
+		ue_per_layer[i] = edac_align_ptr(&ptr, sizeof(u32), count);
+		tot_errcount += 2 * count;
+	}
+
+	edac_dbg(4, "allocating %d error counters\n", tot_errcount);
+	pvt = edac_align_ptr(&ptr, sz_pvt, 1);
+	size = ((unsigned long)pvt) + sz_pvt;
+
+	edac_dbg(1, "allocating %u bytes for mci data (%d %s, %d csrows/channels)\n",
+		 size,
+		 tot_dimms,
+		 per_rank ? "ranks" : "dimms",
+		 tot_csrows * tot_channels);
+
+	mci = kzalloc(size, GFP_KERNEL);
+	if (mci == NULL)
+		return NULL;
+
+	/* Adjust pointers so they point within the memory we just allocated
+	 * rather than an imaginary chunk of memory located at address 0.
+	 */
+	layer = (struct edac_mc_layer *)(((char *)mci) + ((unsigned long)layer));
+	for (i = 0; i < n_layers; i++) {
+		mci->ce_per_layer[i] = (u32 *)((char *)mci + ((unsigned long)ce_per_layer[i]));
+		mci->ue_per_layer[i] = (u32 *)((char *)mci + ((unsigned long)ue_per_layer[i]));
+	}
+	pvt = sz_pvt ? (((char *)mci) + ((unsigned long)pvt)) : NULL;
+
+	/* setup index and various internal pointers */
+	mci->mc_idx = mc_num;
+	mci->tot_dimms = tot_dimms;
+	mci->pvt_info = pvt;
+	mci->n_layers = n_layers;
+	mci->layers = layer;
+	memcpy(mci->layers, layers, sizeof(*layer) * n_layers);
+	mci->nr_csrows = tot_csrows;
+	mci->num_cschannel = tot_channels;
+	mci->csbased = per_rank;
+
+	/*
+	 * Alocate and fill the csrow/channels structs
+	 */
+	mci->csrows = kcalloc(tot_csrows, sizeof(*mci->csrows), GFP_KERNEL);
+	if (!mci->csrows)
+		goto error;
+	for (row = 0; row < tot_csrows; row++) {
+		csr = kzalloc(sizeof(**mci->csrows), GFP_KERNEL);
+		if (!csr)
+			goto error;
+		mci->csrows[row] = csr;
+		csr->csrow_idx = row;
+		csr->mci = mci;
+		csr->nr_channels = tot_channels;
+		csr->channels = kcalloc(tot_channels, sizeof(*csr->channels),
+					GFP_KERNEL);
+		if (!csr->channels)
+			goto error;
+
+		for (chn = 0; chn < tot_channels; chn++) {
+			chan = kzalloc(sizeof(**csr->channels), GFP_KERNEL);
+			if (!chan)
+				goto error;
+			csr->channels[chn] = chan;
+			chan->chan_idx = chn;
+			chan->csrow = csr;
+		}
+	}
+
+	/*
+	 * Allocate and fill the dimm structs
+	 */
+	mci->dimms  = kcalloc(tot_dimms, sizeof(*mci->dimms), GFP_KERNEL);
+	if (!mci->dimms)
+		goto error;
+
+	memset(&pos, 0, sizeof(pos));
+	row = 0;
+	chn = 0;
+	for (i = 0; i < tot_dimms; i++) {
+		chan = mci->csrows[row]->channels[chn];
+		off = EDAC_DIMM_OFF(layer, n_layers, pos[0], pos[1], pos[2]);
+		if (off < 0 || off >= tot_dimms) {
+			edac_mc_printk(mci, KERN_ERR, "EDAC core bug: EDAC_DIMM_OFF is trying to do an illegal data access\n");
+			goto error;
+		}
+
+		dimm = kzalloc(sizeof(**mci->dimms), GFP_KERNEL);
+		if (!dimm)
+			goto error;
+		mci->dimms[off] = dimm;
+		dimm->mci = mci;
+
+		/*
+		 * Copy DIMM location and initialize it.
+		 */
+		len = sizeof(dimm->label);
+		p = dimm->label;
+		n = snprintf(p, len, "mc#%u", mc_num);
+		p += n;
+		len -= n;
+		for (j = 0; j < n_layers; j++) {
+			n = snprintf(p, len, "%s#%u",
+				     edac_layer_name[layers[j].type],
+				     pos[j]);
+			p += n;
+			len -= n;
+			dimm->location[j] = pos[j];
+
+			if (len <= 0)
+				break;
+		}
+
+		/* Link it to the csrows old API data */
+		chan->dimm = dimm;
+		dimm->csrow = row;
+		dimm->cschannel = chn;
+
+		/* Increment csrow location */
+		if (layers[0].is_virt_csrow) {
+			chn++;
+			if (chn == tot_channels) {
+				chn = 0;
+				row++;
+			}
+		} else {
+			row++;
+			if (row == tot_csrows) {
+				row = 0;
+				chn++;
+			}
+		}
+
+		/* Increment dimm location */
+		for (j = n_layers - 1; j >= 0; j--) {
+			pos[j]++;
+			if (pos[j] < layers[j].size)
+				break;
+			pos[j] = 0;
+		}
+	}
+
+	mci->op_state = OP_ALLOC;
+
+	return mci;
+
+error:
+	_edac_mc_free(mci);
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(edac_mc_alloc);
+
+/**
+ * edac_mc_free
+ *	'Free' a previously allocated 'mci' structure
+ * @mci: pointer to a struct mem_ctl_info structure
+ */
+void edac_mc_free(struct mem_ctl_info *mci)
+{
+	edac_dbg(1, "\n");
+
+	/* If we're not yet registered with sysfs free only what was allocated
+	 * in edac_mc_alloc().
+	 */
+	if (!device_is_registered(&mci->dev)) {
+		_edac_mc_free(mci);
+		return;
+	}
+
+	/* the mci instance is freed here, when the sysfs object is dropped */
+	edac_unregister_sysfs(mci);
+}
+EXPORT_SYMBOL_GPL(edac_mc_free);
+
+
+/**
+ * find_mci_by_dev
+ *
+ *	scan list of controllers looking for the one that manages
+ *	the 'dev' device
+ * @dev: pointer to a struct device related with the MCI
+ */
+struct mem_ctl_info *find_mci_by_dev(struct device *dev)
+{
+	struct mem_ctl_info *mci;
+	struct list_head *item;
+
+	edac_dbg(3, "\n");
+
+	list_for_each(item, &mc_devices) {
+		mci = list_entry(item, struct mem_ctl_info, link);
+
+		if (mci->pdev == dev)
+			return mci;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(find_mci_by_dev);
+
+/*
+ * handler for EDAC to check if NMI type handler has asserted interrupt
+ */
+static int edac_mc_assert_error_check_and_clear(void)
+{
+	int old_state;
+
+	if (edac_op_state == EDAC_OPSTATE_POLL)
+		return 1;
+
+	old_state = edac_err_assert;
+	edac_err_assert = 0;
+
+	return old_state;
+}
+
+/*
+ * edac_mc_workq_function
+ *	performs the operation scheduled by a workq request
+ */
+static void edac_mc_workq_function(struct work_struct *work_req)
+{
+	struct delayed_work *d_work = to_delayed_work(work_req);
+	struct mem_ctl_info *mci = to_edac_mem_ctl_work(d_work);
+
+	mutex_lock(&mem_ctls_mutex);
+
+	/* if this control struct has movd to offline state, we are done */
+	if (mci->op_state == OP_OFFLINE) {
+		mutex_unlock(&mem_ctls_mutex);
+		return;
+	}
+
+	/* Only poll controllers that are running polled and have a check */
+	if (edac_mc_assert_error_check_and_clear() && (mci->edac_check != NULL))
+		mci->edac_check(mci);
+
+	mutex_unlock(&mem_ctls_mutex);
+
+	/* Reschedule */
+	queue_delayed_work(edac_workqueue, &mci->work,
+			msecs_to_jiffies(edac_mc_get_poll_msec()));
+}
+
+/*
+ * edac_mc_workq_setup
+ *	initialize a workq item for this mci
+ *	passing in the new delay period in msec
+ *
+ *	locking model:
+ *
+ *		called with the mem_ctls_mutex held
+ */
+static void edac_mc_workq_setup(struct mem_ctl_info *mci, unsigned msec,
+				bool init)
+{
+	edac_dbg(0, "\n");
+
+	/* if this instance is not in the POLL state, then simply return */
+	if (mci->op_state != OP_RUNNING_POLL)
+		return;
+
+	if (init)
+		INIT_DELAYED_WORK(&mci->work, edac_mc_workq_function);
+
+	mod_delayed_work(edac_workqueue, &mci->work, msecs_to_jiffies(msec));
+}
+
+/*
+ * edac_mc_workq_teardown
+ *	stop the workq processing on this mci
+ *
+ *	locking model:
+ *
+ *		called WITHOUT lock held
+ */
+static void edac_mc_workq_teardown(struct mem_ctl_info *mci)
+{
+	int status;
+
+	if (mci->op_state != OP_RUNNING_POLL)
+		return;
+
+	status = cancel_delayed_work(&mci->work);
+	if (status == 0) {
+		edac_dbg(0, "not canceled, flush the queue\n");
+
+		/* workq instance might be running, wait for it */
+		flush_workqueue(edac_workqueue);
+	}
+}
+
+/*
+ * edac_mc_reset_delay_period(unsigned long value)
+ *
+ *	user space has updated our poll period value, need to
+ *	reset our workq delays
+ */
+void edac_mc_reset_delay_period(unsigned long value)
+{
+	struct mem_ctl_info *mci;
+	struct list_head *item;
+
+	mutex_lock(&mem_ctls_mutex);
+
+	list_for_each(item, &mc_devices) {
+		mci = list_entry(item, struct mem_ctl_info, link);
+
+		edac_mc_workq_setup(mci, value, false);
+	}
+
+	mutex_unlock(&mem_ctls_mutex);
+}
+
+
+
+/* Return 0 on success, 1 on failure.
+ * Before calling this function, caller must
+ * assign a unique value to mci->mc_idx.
+ *
+ *	locking model:
+ *
+ *		called with the mem_ctls_mutex lock held
+ */
+static int add_mc_to_global_list(struct mem_ctl_info *mci)
+{
+	struct list_head *item, *insert_before;
+	struct mem_ctl_info *p;
+
+	insert_before = &mc_devices;
+
+	p = find_mci_by_dev(mci->pdev);
+	if (unlikely(p != NULL))
+		goto fail0;
+
+	list_for_each(item, &mc_devices) {
+		p = list_entry(item, struct mem_ctl_info, link);
+
+		if (p->mc_idx >= mci->mc_idx) {
+			if (unlikely(p->mc_idx == mci->mc_idx))
+				goto fail1;
+
+			insert_before = item;
+			break;
+		}
+	}
+
+	list_add_tail_rcu(&mci->link, insert_before);
+	atomic_inc(&edac_handlers);
+	return 0;
+
+fail0:
+	edac_printk(KERN_WARNING, EDAC_MC,
+		"%s (%s) %s %s already assigned %d\n", dev_name(p->pdev),
+		edac_dev_name(mci), p->mod_name, p->ctl_name, p->mc_idx);
+	return 1;
+
+fail1:
+	edac_printk(KERN_WARNING, EDAC_MC,
+		"bug in low-level driver: attempt to assign\n"
+		"    duplicate mc_idx %d in %s()\n", p->mc_idx, __func__);
+	return 1;
+}
+
+static int del_mc_from_global_list(struct mem_ctl_info *mci)
+{
+	int handlers = atomic_dec_return(&edac_handlers);
+	list_del_rcu(&mci->link);
+
+	/* these are for safe removal of devices from global list while
+	 * NMI handlers may be traversing list
+	 */
+	synchronize_rcu();
+	INIT_LIST_HEAD(&mci->link);
+
+	return handlers;
+}
+
+/**
+ * edac_mc_find: Search for a mem_ctl_info structure whose index is 'idx'.
+ *
+ * If found, return a pointer to the structure.
+ * Else return NULL.
+ *
+ * Caller must hold mem_ctls_mutex.
+ */
+struct mem_ctl_info *edac_mc_find(int idx)
+{
+	struct list_head *item;
+	struct mem_ctl_info *mci;
+
+	list_for_each(item, &mc_devices) {
+		mci = list_entry(item, struct mem_ctl_info, link);
+
+		if (mci->mc_idx >= idx) {
+			if (mci->mc_idx == idx)
+				return mci;
+
+			break;
+		}
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL(edac_mc_find);
+
+/**
+ * edac_mc_add_mc_with_groups: Insert the 'mci' structure into the mci
+ *	global list and create sysfs entries associated with mci structure
+ * @mci: pointer to the mci structure to be added to the list
+ * @groups: optional attribute groups for the driver-specific sysfs entries
+ *
+ * Return:
+ *	0	Success
+ *	!0	Failure
+ */
+
+/* FIXME - should a warning be printed if no error detection? correction? */
+int edac_mc_add_mc_with_groups(struct mem_ctl_info *mci,
+			       const struct attribute_group **groups)
+{
+	int ret = -EINVAL;
+	edac_dbg(0, "\n");
+
+	if (mci->mc_idx >= EDAC_MAX_MCS) {
+		pr_warn_once("Too many memory controllers: %d\n", mci->mc_idx);
+		return -ENODEV;
+	}
+
+#ifdef CONFIG_EDAC_DEBUG
+	if (edac_debug_level >= 3)
+		edac_mc_dump_mci(mci);
+
+	if (edac_debug_level >= 4) {
+		int i;
+
+		for (i = 0; i < mci->nr_csrows; i++) {
+			struct csrow_info *csrow = mci->csrows[i];
+			u32 nr_pages = 0;
+			int j;
+
+			for (j = 0; j < csrow->nr_channels; j++)
+				nr_pages += csrow->channels[j]->dimm->nr_pages;
+			if (!nr_pages)
+				continue;
+			edac_mc_dump_csrow(csrow);
+			for (j = 0; j < csrow->nr_channels; j++)
+				if (csrow->channels[j]->dimm->nr_pages)
+					edac_mc_dump_channel(csrow->channels[j]);
+		}
+		for (i = 0; i < mci->tot_dimms; i++)
+			if (mci->dimms[i]->nr_pages)
+				edac_mc_dump_dimm(mci->dimms[i], i);
+	}
+#endif
+	mutex_lock(&mem_ctls_mutex);
+
+	if (edac_mc_owner && edac_mc_owner != mci->mod_name) {
+		ret = -EPERM;
+		goto fail0;
+	}
+
+	if (add_mc_to_global_list(mci))
+		goto fail0;
+
+	/* set load time so that error rate can be tracked */
+	mci->start_time = jiffies;
+
+	mci->bus = &mc_bus[mci->mc_idx];
+
+	if (edac_create_sysfs_mci_device(mci, groups)) {
+		edac_mc_printk(mci, KERN_WARNING,
+			"failed to create sysfs device\n");
+		goto fail1;
+	}
+
+	/* If there IS a check routine, then we are running POLLED */
+	if (mci->edac_check != NULL) {
+		/* This instance is NOW RUNNING */
+		mci->op_state = OP_RUNNING_POLL;
+
+		edac_mc_workq_setup(mci, edac_mc_get_poll_msec(), true);
+	} else {
+		mci->op_state = OP_RUNNING_INTERRUPT;
+	}
+
+	/* Report action taken */
+	edac_mc_printk(mci, KERN_INFO,
+		"Giving out device to module %s controller %s: DEV %s (%s)\n",
+		mci->mod_name, mci->ctl_name, mci->dev_name,
+		edac_op_state_to_string(mci->op_state));
+
+	edac_mc_owner = mci->mod_name;
+
+	mutex_unlock(&mem_ctls_mutex);
+	return 0;
+
+fail1:
+	del_mc_from_global_list(mci);
+
+fail0:
+	mutex_unlock(&mem_ctls_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(edac_mc_add_mc_with_groups);
+
+/**
+ * edac_mc_del_mc: Remove sysfs entries for specified mci structure and
+ *                 remove mci structure from global list
+ * @pdev: Pointer to 'struct device' representing mci structure to remove.
+ *
+ * Return pointer to removed mci structure, or NULL if device not found.
+ */
+struct mem_ctl_info *edac_mc_del_mc(struct device *dev)
+{
+	struct mem_ctl_info *mci;
+
+	edac_dbg(0, "\n");
+
+	mutex_lock(&mem_ctls_mutex);
+
+	/* find the requested mci struct in the global list */
+	mci = find_mci_by_dev(dev);
+	if (mci == NULL) {
+		mutex_unlock(&mem_ctls_mutex);
+		return NULL;
+	}
+
+	if (!del_mc_from_global_list(mci))
+		edac_mc_owner = NULL;
+	mutex_unlock(&mem_ctls_mutex);
+
+	/* flush workq processes */
+	edac_mc_workq_teardown(mci);
+
+	/* marking MCI offline */
+	mci->op_state = OP_OFFLINE;
+
+	/* remove from sysfs */
+	edac_remove_sysfs_mci_device(mci);
+
+	edac_printk(KERN_INFO, EDAC_MC,
+		"Removed device %d for %s %s: DEV %s\n", mci->mc_idx,
+		mci->mod_name, mci->ctl_name, edac_dev_name(mci));
+
+	return mci;
+}
+EXPORT_SYMBOL_GPL(edac_mc_del_mc);
+
+static void edac_mc_scrub_block(unsigned long page, unsigned long offset,
+				u32 size)
+{
+	struct page *pg;
+	void *virt_addr;
+	unsigned long flags = 0;
+
+	edac_dbg(3, "\n");
+
+	/* ECC error page was not in our memory. Ignore it. */
+	if (!pfn_valid(page))
+		return;
+
+	/* Find the actual page structure then map it and fix */
+	pg = pfn_to_page(page);
+
+	if (PageHighMem(pg))
+		local_irq_save(flags);
+
+	virt_addr = kmap_atomic(pg);
+
+	/* Perform architecture specific atomic scrub operation */
+	atomic_scrub(virt_addr + offset, size);
+
+	/* Unmap and complete */
+	kunmap_atomic(virt_addr);
+
+	if (PageHighMem(pg))
+		local_irq_restore(flags);
+}
+
+/* FIXME - should return -1 */
+int edac_mc_find_csrow_by_page(struct mem_ctl_info *mci, unsigned long page)
+{
+	struct csrow_info **csrows = mci->csrows;
+	int row, i, j, n;
+
+	edac_dbg(1, "MC%d: 0x%lx\n", mci->mc_idx, page);
+	row = -1;
+
+	for (i = 0; i < mci->nr_csrows; i++) {
+		struct csrow_info *csrow = csrows[i];
+		n = 0;
+		for (j = 0; j < csrow->nr_channels; j++) {
+			struct dimm_info *dimm = csrow->channels[j]->dimm;
+			n += dimm->nr_pages;
+		}
+		if (n == 0)
+			continue;
+
+		edac_dbg(3, "MC%d: first(0x%lx) page(0x%lx) last(0x%lx) mask(0x%lx)\n",
+			 mci->mc_idx,
+			 csrow->first_page, page, csrow->last_page,
+			 csrow->page_mask);
+
+		if ((page >= csrow->first_page) &&
+		    (page <= csrow->last_page) &&
+		    ((page & csrow->page_mask) ==
+		     (csrow->first_page & csrow->page_mask))) {
+			row = i;
+			break;
+		}
+	}
+
+	if (row == -1)
+		edac_mc_printk(mci, KERN_ERR,
+			"could not look up page error address %lx\n",
+			(unsigned long)page);
+
+	return row;
+}
+EXPORT_SYMBOL_GPL(edac_mc_find_csrow_by_page);
+
+const char *edac_layer_name[] = {
+	[EDAC_MC_LAYER_BRANCH] = "branch",
+	[EDAC_MC_LAYER_CHANNEL] = "channel",
+	[EDAC_MC_LAYER_SLOT] = "slot",
+	[EDAC_MC_LAYER_CHIP_SELECT] = "csrow",
+	[EDAC_MC_LAYER_ALL_MEM] = "memory",
+};
+EXPORT_SYMBOL_GPL(edac_layer_name);
+
+static void edac_inc_ce_error(struct mem_ctl_info *mci,
+			      bool enable_per_layer_report,
+			      const int pos[EDAC_MAX_LAYERS],
+			      const u16 count)
+{
+	int i, index = 0;
+
+	mci->ce_mc += count;
+
+	if (!enable_per_layer_report) {
+		mci->ce_noinfo_count += count;
+		return;
+	}
+
+	for (i = 0; i < mci->n_layers; i++) {
+		if (pos[i] < 0)
+			break;
+		index += pos[i];
+		mci->ce_per_layer[i][index] += count;
+
+		if (i < mci->n_layers - 1)
+			index *= mci->layers[i + 1].size;
+	}
+}
+
+static void edac_inc_ue_error(struct mem_ctl_info *mci,
+				    bool enable_per_layer_report,
+				    const int pos[EDAC_MAX_LAYERS],
+				    const u16 count)
+{
+	int i, index = 0;
+
+	mci->ue_mc += count;
+
+	if (!enable_per_layer_report) {
+		mci->ce_noinfo_count += count;
+		return;
+	}
+
+	for (i = 0; i < mci->n_layers; i++) {
+		if (pos[i] < 0)
+			break;
+		index += pos[i];
+		mci->ue_per_layer[i][index] += count;
+
+		if (i < mci->n_layers - 1)
+			index *= mci->layers[i + 1].size;
+	}
+}
+
+static void edac_ce_error(struct mem_ctl_info *mci,
+			  const u16 error_count,
+			  const int pos[EDAC_MAX_LAYERS],
+			  const char *msg,
+			  const char *location,
+			  const char *label,
+			  const char *detail,
+			  const char *other_detail,
+			  const bool enable_per_layer_report,
+			  const unsigned long page_frame_number,
+			  const unsigned long offset_in_page,
+			  long grain)
+{
+	unsigned long remapped_page;
+	char *msg_aux = "";
+
+	if (*msg)
+		msg_aux = " ";
+
+	if (edac_mc_get_log_ce()) {
+		if (other_detail && *other_detail)
+			edac_mc_printk(mci, KERN_WARNING,
+				       "%d CE %s%son %s (%s %s - %s)\n",
+				       error_count, msg, msg_aux, label,
+				       location, detail, other_detail);
+		else
+			edac_mc_printk(mci, KERN_WARNING,
+				       "%d CE %s%son %s (%s %s)\n",
+				       error_count, msg, msg_aux, label,
+				       location, detail);
+	}
+	edac_inc_ce_error(mci, enable_per_layer_report, pos, error_count);
+
+	if (mci->scrub_mode == SCRUB_SW_SRC) {
+		/*
+			* Some memory controllers (called MCs below) can remap
+			* memory so that it is still available at a different
+			* address when PCI devices map into memory.
+			* MC's that can't do this, lose the memory where PCI
+			* devices are mapped. This mapping is MC-dependent
+			* and so we call back into the MC driver for it to
+			* map the MC page to a physical (CPU) page which can
+			* then be mapped to a virtual page - which can then
+			* be scrubbed.
+			*/
+		remapped_page = mci->ctl_page_to_phys ?
+			mci->ctl_page_to_phys(mci, page_frame_number) :
+			page_frame_number;
+
+		edac_mc_scrub_block(remapped_page,
+					offset_in_page, grain);
+	}
+}
+
+static void edac_ue_error(struct mem_ctl_info *mci,
+			  const u16 error_count,
+			  const int pos[EDAC_MAX_LAYERS],
+			  const char *msg,
+			  const char *location,
+			  const char *label,
+			  const char *detail,
+			  const char *other_detail,
+			  const bool enable_per_layer_report)
+{
+	char *msg_aux = "";
+
+	if (*msg)
+		msg_aux = " ";
+
+	if (edac_mc_get_log_ue()) {
+		if (other_detail && *other_detail)
+			edac_mc_printk(mci, KERN_WARNING,
+				       "%d UE %s%son %s (%s %s - %s)\n",
+				       error_count, msg, msg_aux, label,
+				       location, detail, other_detail);
+		else
+			edac_mc_printk(mci, KERN_WARNING,
+				       "%d UE %s%son %s (%s %s)\n",
+				       error_count, msg, msg_aux, label,
+				       location, detail);
+	}
+
+	if (edac_mc_get_panic_on_ue()) {
+		if (other_detail && *other_detail)
+			panic("UE %s%son %s (%s%s - %s)\n",
+			      msg, msg_aux, label, location, detail, other_detail);
+		else
+			panic("UE %s%son %s (%s%s)\n",
+			      msg, msg_aux, label, location, detail);
+	}
+
+	edac_inc_ue_error(mci, enable_per_layer_report, pos, error_count);
+}
+
+/**
+ * edac_raw_mc_handle_error - reports a memory event to userspace without doing
+ *			      anything to discover the error location
+ *
+ * @type:		severity of the error (CE/UE/Fatal)
+ * @mci:		a struct mem_ctl_info pointer
+ * @e:			error description
+ *
+ * This raw function is used internally by edac_mc_handle_error(). It should
+ * only be called directly when the hardware error come directly from BIOS,
+ * like in the case of APEI GHES driver.
+ */
+void edac_raw_mc_handle_error(const enum hw_event_mc_err_type type,
+			      struct mem_ctl_info *mci,
+			      struct edac_raw_error_desc *e)
+{
+	char detail[80];
+	int pos[EDAC_MAX_LAYERS] = { e->top_layer, e->mid_layer, e->low_layer };
+
+	/* Memory type dependent details about the error */
+	if (type == HW_EVENT_ERR_CORRECTED) {
+		snprintf(detail, sizeof(detail),
+			"page:0x%lx offset:0x%lx grain:%ld syndrome:0x%lx",
+			e->page_frame_number, e->offset_in_page,
+			e->grain, e->syndrome);
+		edac_ce_error(mci, e->error_count, pos, e->msg, e->location, e->label,
+			      detail, e->other_detail, e->enable_per_layer_report,
+			      e->page_frame_number, e->offset_in_page, e->grain);
+	} else {
+		snprintf(detail, sizeof(detail),
+			"page:0x%lx offset:0x%lx grain:%ld",
+			e->page_frame_number, e->offset_in_page, e->grain);
+
+		edac_ue_error(mci, e->error_count, pos, e->msg, e->location, e->label,
+			      detail, e->other_detail, e->enable_per_layer_report);
+	}
+
+
+}
+EXPORT_SYMBOL_GPL(edac_raw_mc_handle_error);
+
+/**
+ * edac_mc_handle_error - reports a memory event to userspace
+ *
+ * @type:		severity of the error (CE/UE/Fatal)
+ * @mci:		a struct mem_ctl_info pointer
+ * @error_count:	Number of errors of the same type
+ * @page_frame_number:	mem page where the error occurred
+ * @offset_in_page:	offset of the error inside the page
+ * @syndrome:		ECC syndrome
+ * @top_layer:		Memory layer[0] position
+ * @mid_layer:		Memory layer[1] position
+ * @low_layer:		Memory layer[2] position
+ * @msg:		Message meaningful to the end users that
+ *			explains the event
+ * @other_detail:	Technical details about the event that
+ *			may help hardware manufacturers and
+ *			EDAC developers to analyse the event
+ */
+void edac_mc_handle_error(const enum hw_event_mc_err_type type,
+			  struct mem_ctl_info *mci,
+			  const u16 error_count,
+			  const unsigned long page_frame_number,
+			  const unsigned long offset_in_page,
+			  const unsigned long syndrome,
+			  const int top_layer,
+			  const int mid_layer,
+			  const int low_layer,
+			  const char *msg,
+			  const char *other_detail)
+{
+	char *p;
+	int row = -1, chan = -1;
+	int pos[EDAC_MAX_LAYERS] = { top_layer, mid_layer, low_layer };
+	int i, n_labels = 0;
+	u8 grain_bits;
+	struct edac_raw_error_desc *e = &mci->error_desc;
+
+	edac_dbg(3, "MC%d\n", mci->mc_idx);
+
+	/* Fills the error report buffer */
+	memset(e, 0, sizeof (*e));
+	e->error_count = error_count;
+	e->top_layer = top_layer;
+	e->mid_layer = mid_layer;
+	e->low_layer = low_layer;
+	e->page_frame_number = page_frame_number;
+	e->offset_in_page = offset_in_page;
+	e->syndrome = syndrome;
+	e->msg = msg;
+	e->other_detail = other_detail;
+
+	/*
+	 * Check if the event report is consistent and if the memory
+	 * location is known. If it is known, enable_per_layer_report will be
+	 * true, the DIMM(s) label info will be filled and the per-layer
+	 * error counters will be incremented.
+	 */
+	for (i = 0; i < mci->n_layers; i++) {
+		if (pos[i] >= (int)mci->layers[i].size) {
+
+			edac_mc_printk(mci, KERN_ERR,
+				       "INTERNAL ERROR: %s value is out of range (%d >= %d)\n",
+				       edac_layer_name[mci->layers[i].type],
+				       pos[i], mci->layers[i].size);
+			/*
+			 * Instead of just returning it, let's use what's
+			 * known about the error. The increment routines and
+			 * the DIMM filter logic will do the right thing by
+			 * pointing the likely damaged DIMMs.
+			 */
+			pos[i] = -1;
+		}
+		if (pos[i] >= 0)
+			e->enable_per_layer_report = true;
+	}
+
+	/*
+	 * Get the dimm label/grain that applies to the match criteria.
+	 * As the error algorithm may not be able to point to just one memory
+	 * stick, the logic here will get all possible labels that could
+	 * pottentially be affected by the error.
+	 * On FB-DIMM memory controllers, for uncorrected errors, it is common
+	 * to have only the MC channel and the MC dimm (also called "branch")
+	 * but the channel is not known, as the memory is arranged in pairs,
+	 * where each memory belongs to a separate channel within the same
+	 * branch.
+	 */
+	p = e->label;
+	*p = '\0';
+
+	for (i = 0; i < mci->tot_dimms; i++) {
+		struct dimm_info *dimm = mci->dimms[i];
+
+		if (top_layer >= 0 && top_layer != dimm->location[0])
+			continue;
+		if (mid_layer >= 0 && mid_layer != dimm->location[1])
+			continue;
+		if (low_layer >= 0 && low_layer != dimm->location[2])
+			continue;
+
+		/* get the max grain, over the error match range */
+		if (dimm->grain > e->grain)
+			e->grain = dimm->grain;
+
+		/*
+		 * If the error is memory-controller wide, there's no need to
+		 * seek for the affected DIMMs because the whole
+		 * channel/memory controller/...  may be affected.
+		 * Also, don't show errors for empty DIMM slots.
+		 */
+		if (e->enable_per_layer_report && dimm->nr_pages) {
+			if (n_labels >= EDAC_MAX_LABELS) {
+				e->enable_per_layer_report = false;
+				break;
+			}
+			n_labels++;
+			if (p != e->label) {
+				strcpy(p, OTHER_LABEL);
+				p += strlen(OTHER_LABEL);
+			}
+			strcpy(p, dimm->label);
+			p += strlen(p);
+			*p = '\0';
+
+			/*
+			 * get csrow/channel of the DIMM, in order to allow
+			 * incrementing the compat API counters
+			 */
+			edac_dbg(4, "%s csrows map: (%d,%d)\n",
+				 mci->csbased ? "rank" : "dimm",
+				 dimm->csrow, dimm->cschannel);
+			if (row == -1)
+				row = dimm->csrow;
+			else if (row >= 0 && row != dimm->csrow)
+				row = -2;
+
+			if (chan == -1)
+				chan = dimm->cschannel;
+			else if (chan >= 0 && chan != dimm->cschannel)
+				chan = -2;
+		}
+	}
+
+	if (!e->enable_per_layer_report) {
+		strcpy(e->label, "any memory");
+	} else {
+		edac_dbg(4, "csrow/channel to increment: (%d,%d)\n", row, chan);
+		if (p == e->label)
+			strcpy(e->label, "unknown memory");
+		if (type == HW_EVENT_ERR_CORRECTED) {
+			if (row >= 0) {
+				mci->csrows[row]->ce_count += error_count;
+				if (chan >= 0)
+					mci->csrows[row]->channels[chan]->ce_count += error_count;
+			}
+		} else
+			if (row >= 0)
+				mci->csrows[row]->ue_count += error_count;
+	}
+
+	/* Fill the RAM location data */
+	p = e->location;
+
+	for (i = 0; i < mci->n_layers; i++) {
+		if (pos[i] < 0)
+			continue;
+
+		p += sprintf(p, "%s:%d ",
+			     edac_layer_name[mci->layers[i].type],
+			     pos[i]);
+	}
+	if (p > e->location)
+		*(p - 1) = '\0';
+
+	/* Report the error via the trace interface */
+	grain_bits = fls_long(e->grain) + 1;
+	trace_mc_event(type, e->msg, e->label, e->error_count,
+		       mci->mc_idx, e->top_layer, e->mid_layer, e->low_layer,
+		       PAGES_TO_MiB(e->page_frame_number) | e->offset_in_page,
+		       grain_bits, e->syndrome, e->other_detail);
+
+	edac_raw_mc_handle_error(type, mci, e);
+}
+EXPORT_SYMBOL_GPL(edac_mc_handle_error);